The subject of the invention is a delivery unit, with a baffle, with a fuel pump arranged therein and with a radial-onflow filter which is arranged on the bottom of the baffle and which is formed by shaped elements projecting axially from the bottom of the baffle, so that an axially running gap is formed in each case between two adjacent shaped elements in each case, and which surrounds an inlet port arranged in the bottom of the baffle. The delivery unit serves for delivering fuel out of the fuel tank to an internal combustion engine of a motor vehicle.
It is known to use delivery units of this type in fuel tanks. Impurities contained in the fuel may enter the fuel pump and damage this. In order to protect the fuel pump against these impurities, the fuel sucked in by the fuel pump is filtered. For this purpose, the fuel pump is preceded by a coarse filter, so that the particles, which could lead to damage to the fuel pump, are kept away from the suction-intake region of the fuel pump.
In addition to various forms of filter construction which are additionally mounted as separate parts on the baffle, it is known to arrange a filter crown on the bottom of the baffle. The filter crown is formed by shaped portions provided on the bottom of the baffle. These shaped portions are arranged at a distance from one another and serve at the same time as a standing surface for the baffle. When the baffle stands on the bottom of the fuel tank, the shaped portions form a filter of the radial-onflow type with axially running gaps. The inlet port, through which the prefiltered fuel enters the baffle, is located within this crown of shaped portions. The width of the axially running gaps is in this case a measure of the degree of filtering of the gap filter. The disadvantage of this device is that, due to the small width of the axially running gaps, the throughflow cross section for the fuel flowing to the inlet port is reduced. In order to ensure a sufficient supply of fuel to the suction-intake port, a specific throughflow cross section should not be undershot. Consequently, the gap width selected cannot be as small as desired, and therefore the degree of filtering of the gap filter is limited.
The object on which the present invention is based is, therefore, to provide a delivery unit with a filter which both provides sufficient fuel for the suction-intake port and possesses a high degree of filtering.